Acetic acid can be neutralized with sodium bicarbonate. The products of neutralization are H2O, CO2, and sodium acetate, NaC2H3O2. Carbon dioxide,CO2, escapes as a gas. Sodium acetate dissolves in water. So, the excess of acetic acid is first converted to other compounds that can be easily removed with the water layer. What remains is isopentyl alcohol which has low solubility in water and exists as a separate layer that can be isolated easily by pouring out one layer at a time from the separatory funnel.